1. Field of the Invention
The present invention relates to a semiconductor light-receiving element.
2. Description of Related Art
A common conventional semiconductor light-receiving element (photodiode) performs optoelectric conversion in which light incident on a light-receiving surface is diverted to the depletion layer of a light-absorbing layer immediately below a diffusion region.
An example of such a semiconductor light-receiving element is disclosed in Reference I (Japanese Unexamined Patent Application (Kokai) 8-18088). The semiconductor light-receiving element of Reference I prevents stray light from being generated because light from outside the light-receiving surface is blocked by a shielding metal film provided along the perimeter of the light-receiving surface. In addition, the shielding metal film does not create stray capacitance because this shielding metal film is electrically connected to a window layer via an ohmic electrode. Consequently, using the technique of Reference I makes it possible to realize a semiconductor light-receiving element having excellent element characteristics.
It is known, however, that outside force, stress, or the like causes cracking or chipping on the surface of a semiconductor light-receiving element during production or operation of this element. Consequently, the substrate around the light-receiving surface is commonly cracked or chipped during production or operation. Such cracking of chipping is not limited to the technique disclosed in Reference I.
For example, dicing, scribing or the like (hereinafter referred to as "dicing or the like"), is used in an element splitting process in which a plurality of semiconductor light-receiving elements formed as an array on a wafer are cut and separated. Wafers are commonly cut while being bonded to a wafer sheet or the like. When cracks form near the cutting surface during the cutting of wafers by dicing or the like, these cracks grow during the operation of the semiconductor light-receiving element, sometimes reaching the diffusion region. In a common semiconductor light-receiving element, a crack reaching all the way into the diffusion region alters element characteristics or causes element failure. The above-described excellent element characteristics are adversely affected as a result.
In the semiconductor light-receiving element of Reference I, an ohmic electrode is provided, for example, on opposite sides (areas that face each other) of a substrate surface, but these opposite-side areas of the substrate surface occasionally break off.
Such breakage occurs, for example, when a semiconductor light-receiving element is handled by pincers or the like during the mounting of the element. In the process, the shielding metal film is brought into an electrically floating state if the ohmic electrode on the opposite sides of the substrate surface has broken off. The above-described excellent element characteristics are adversely affected as a result.